Now I want to start with OC'ing the card to see how far I can push it - but I have no experience with OC'ing graphics cards yet.

So I downloaded EVGA's tools Precision, E-LEET and OC Scanner.
Without touching the voltages I raised the Core-Clock to 983MHz (linked with the Shader-Clock).
I ran OC Scanner for about 5 mins, temps raised to a maximum of 41°C, OC scanner reported a total of 13 artifacts.

So what does it mean now?
How can I really test for stability?
Will I experience driver resets or the like if I go too high with the clock?
When do I need to raise the voltage?
Why is E-LEET limiting the maximum voltage to 1.15 Volts?

Wow.. not a single response.. must have been really silly questions.. sorry for that.

To answer my own questions:

1) So what does it mean?

Nothing. E.g. Furmark runs fine while 3dMark11 (the driver) was crashing during benchmark.

2) How can I really test for stability.

3Dmark11 benchmark + BF3 1/2 hour.

3) Will I experience driver resets or the like if I go too high with the clock?

yes.

4) When do I need to raise the voltage?

Whenever the driver crashes.

5) Why is E-LEET limiting the maximum voltage to 1.15 Volts?

The bios locks to 1.15 Volts max. Needs modified Bios to unlock higher voltage settings. Will use NiBiTor for that.

So far I was able to push the card to 980 MHZ Core-clock (synced with Shader-clock) and 2220 MHz using 1.15 Volts.
It seems that I can go higher with the mem, but it has only little effect on the 3Dmark11 results.
Temp for the GPU maxed out at 42°C after 1/2 hour BF3 with my current WC setup.Edited by Becks21 - 12/30/11 at 4:23pm